In general, the field to which the present invention relates is that of producing chlorinated derivatives of ethylene, such as vinyl and vinylidene halides, particularly vinyl chloride. Also closely connected therewith is the synthesis of chlorinated solvents from, ethylene, chlorine and/or hydrogen chloride. Among such solvents are the highly chlorinated ethylenes, such as perchloroethylene, which is made by a process in which ethylene and/or partially chlorinated ethanes are subjected to one or more steps of catalytic oxyhydrochlorination with hydrogen chloride and oxygen.
Vinyl chloride is prepared by various processes from ethylene, elemental chlorine, and/or hydrogen chloride in most all of which a cracking step is employed wherein ethylene dichloride is thermally cracked in the vapor phase under pressure to vinyl chloride and by-product hydrogen chloride. The latter is recovered by an oxyhydrochlorination step wherein the hydrogen chloride is reacted with additional ethylene and oxygen to produce dichloroethanes which in turn are recycled to the cracking step. In many processes, a direct chlorination step is also employed wherein ethylene and elemental chlorine are reacted in liquid phase to produce dichloroethanes which are then cracked to vinyl chloride.
In all of these known solvent and monomer processes, the desired direct chlorination, oxyhydrochlorination, and/or cracking steps are not 100% selective to the desired chlorohydrocarbon end product and, as a result, fairly large quantities of undesired chlorine-containing by-products are obtained as complex mixtures which range in composition from chloroform or ethyl chloride to trichloroethanes and trichloroethylenes, tetrachloroethanes, hexachloroethanes, hexachlorobutadiene, etc., as well as aromatic compounds. Obviously, these undesirable chlorine-containing by-products pose economic, as well as ecological, problems of disposal.
Therefore, it would be most desirable and beneficial to have a process for producing chlorinated derivatives of ethylene and chlorinated solvents from ethylene, chlorine and/or hydrogen chloride wherein the heat energy product is utilized in the process and the production of unwanted chlorinated hydrocarbon by-products is substantially eliminated, or the end result is insignificant, due to reutilization of the waste products in the process.